Conventional primary systems for performing aerial refueling operations between a tanker aircraft and a receiver aircraft are the boom refueling system and the probe and drogue system.
The boom refueling system is based on the use of a boom device for interconnecting a tanker aircraft with a receiver aircraft or receptor in flight, the boom device being basically a telescopic or extensible tube attached to the underside of the tanker aircraft by means of an articulation element, therefore providing fuel passage from the tanker aircraft to the receiver aircraft. At the tanker aircraft, the operator controls visually all steps and procedures for a safe refueling operation, including maneuvering the boom device into a position appropriate for coupling with a receiver aircraft. From the tanker, the operator controls the boom movements and therefore manipulates the boom device until it makes a physical connection with the receptacle of the approaching receptor aircraft. Once the refueling operation is finished in a certain session, the boom is hoisted up to its secured position in the tanker aircraft.
In the probe and drogue system, a refueling hose having a drogue on one end is extended behind the tanker, to a position within a suitable range of the receiver aircraft. The receiver aircraft has a probe that must be coupled into the drogue, and after approaching, the refueling position is flown to mate the probe with the drogue.
Moreover, for both types of in-flight refueling systems, the operator at the tanker aircraft may be in some cases remotely positioned with respect to the boom device and drogue system, such that he controls the in-flight refueling operation via image capture operation.
Refueling operations, and in particular the approximation operation of the boom device relative to the receiver aircraft, is very sensitive and must be effected in a very precise and accurate way because of security reasons.
In the cases mentioned before, when refueling operations are being performed (using whichever of the systems that have been previously disclosed), and especially at night and sometimes under bad weather conditions, there exists the need of providing illuminating systems to properly illuminate the area of the receiver aircraft in which the refueling operation is to be performed.
Document U.S. Pat. No. 4,398,685 discloses a refueling system for a tanker aircraft comprising means for illuminating a receiver aircraft with infrared light (eye-safe light) providing a “refueling envelope”, which is defined as that volume of space behind the tanker aircraft, within which limits the refueling boom may be maneuvered horizontally and vertically and extended or retracted without imposing undesirable stress on the refueling boom. Document U.S. Pat. No. 4,398,685 also discloses a refueling system further comprising means enabling the pilot of the receiver aircraft to view the tanker aircraft without interference from glare so as to accurately maneuver the receiver aircraft into a suitable position for effecting interconnection with the boom, with minimum communication between tanker and receiver aircraft. Some drawbacks of this system are: the large electrical power supply, the large amount of excess heat and the large amounts of light in the visible wavelengths such that may hamper the vision of an operator in the receiver aircraft, which additionally may be visible for hostile observers.
Document EP 1751001 discloses an illuminating system that provides eye-safe and covert illumination adapted to uniformly illuminate an area of a first aircraft that may contain an in-flight refueling position, the system comprising a directing device configured to direct the emission, said emission being adapted to define an adjustable emission envelope containing a plurality of in-flight refueling positions. This system comprises a generating device configured to generate emission such that the emission is eye safe, being this a serious limitation in power, which may result in a inadequate illumination or a limited illuminated area.
There exists the need, however, of providing an illuminating system of a greater power therefore providing a higher illumination in order to overcome adverse situations such as lack of visibility or bad weather conditions. The known systems have a certain limit of power actuation because the light generating means need to provide eye-safe emissions.
The present invention is intended to solve said disadvantages.